Liquid crystal (LC) based devices are used to alter polarization of light passing through or reflected from such devices. A change in polarization is induced within the device by applying a potential difference across a liquid crystal layer thereof. Conventional LC based devices have a liquid crystal layer typically a few micrometers thick, the thickness having the effect of altering the twist of the liquid crystal layer thereby changing the ability of the liquid crystal layer to rotate the polarization angle of light.
The change in polarization can be detected by passing a beam reflected from or transmitted through the LC based device through a polarizer filter, which only allows light of a certain polarization to pass through or be reflected. This principle has been widely used to make cheap, passive matrix text and graphic displays, and more recently to make large-area display screens using active matrix transistor thin film (TFT) technology.
Conventional LC based devices have one or both surfaces formed by an external layer formed of a light transmissive medium such as glass to allow light from outside the device to pass through the external layer to an adjoining liquid crystal layer. In addition to being light transmissive, the external layer is also typically non-resilient due to material used and/or thickness of the layer in order to provide structural strength for the LC based device during fabrication (such as the afore-mentioned large area display screens).
The thick external layers composed of, for example, glass may be thinned by mechanical or chemical means. However, chemical thinning requires use of a main chemical that is concentrated hydrofluoric acid solutions (e.g., up to 48% HCl). Such chemicals are hazardous and present challenges when incorporating their use in the device fabrication process. Furthermore, chemical thinning does not necessarily produce a smooth surface as the achievable smoothness depends on the composition of the glass layer.
Alternatively, a thinner glass plate can be provided as the external layer during assembly. However, glass sheets having a thickness less than one millimeter are fragile and easily broken, particularly if the sheets encompass a large surface areas. Conventional minimum glass thicknesses which for use over relatively small areas (e.g., 1×1 cm2) is typically half a millimeter; for large areas typically one millimeter is required making use of such glass sheets for thinner layers impractical.
Thus, what is needed is a method for fabricating a thin-surface (i.e., thin external layer) liquid crystal based sensor device. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background of the disclosure.